Safety tubes or the like



De- 29, 1942- F. A. KRusEMARK l 2,307,002

SAFETY TUBES OR THE LIKE Filed NOV. 22, 1939 Patented Dee. 29, 1942anima UNE''ED STATES PARENT @FFME SAFETY TUBES 0R THE LIKE Frederick A.Krusemark, Chicago, Ill. Application 'November 22, 1939, Serial No.305,608

11 Claims.

This invention has to do with safety tubes or the like for use inautomobiles and other vehicles using air-inflated tires and tubes. It isa continuation in part of the subject matter contained in my patentapplication, Serial No. 247,334, filed December 23, 1938, on Safetytubes, which matured into Patent 2,264,164 November 25, 1941.

It is a purpose to provide a safety tube of the generally describedmultiple chamber type, in which one of the chambers fits over the -otherchamber, in a manner generally crescent-shaped in cross-section, as setout and described in my previous application, but in which in thisapplication the base portions of the outer chamber are fastened togetheracross the base of the inner air chamber.

It is a further object to provide a fastening means which issubstantially continuous in longitudinal area of the safety tube, butwhich itself usually contains no air or inliating uid, merely servingthe purpose of tieing the base portions of one air chamber unit of thesafety tube together generally across the base of the other air chamberunit of the safety tube, and the other purposes described below, It isanother purpose and object of the invention to provide a substantiallycontinuous lengthwise strip of material which fastens the base portionsof one air chamber unit of the safety tube together, and which acts atthe same time as a protecting flap or shield for the base portion of asecond air chamber unit of the safety tube.

It is a further object of the invention to provide a device as describedabove, which is preferably of yieldable flexible material designed toexpand to allow the base of the air chamber unit it protects to movedown into the well of the rim upon inflation, but which preferably willnot ordinarily cause the outer air chamber unit, the bases of which aretied together by said strip of material to follow more than a limitedamount. In other words the strip of material preferably is yieldableenough to permit the base of the inner air chamber unit to enter theWell of the rim, and is still strong enough to hold the base portions ofthe outer air chamber unit in relative position, thus generallyeliminating the necessity of a bead, but still permitting the bases ofthe outer air chamber unit to remain substantially adjacent the bead ofthe tire.

t is a further object to provide a structure in which the bases of theouter air chamber unit are in nowise connected directly to the base ofthe inner air chamber unit, but are connected 55 practically all to eachother across the base of the inner air chamber unit in such a way thatthey operate substantially independently from the operation of the baseof the inner air chamber unit, and the base portions or the outer airchamber unit and flap across the base portion of the inner air chamberunit form additional protection against injury to the base of the innerair chamber unit.

It is a further object of the invention to provide a flap which ispreferably in effect a continuation'of the material and construction ofthe outer wall portion of the outer air chamber unit but which flap initself does not enclose any air chamber; that is, a nap designed toeliminate air between it and the base of the inner air chamber unit,thus allowing the base of the inner air chamber unit a freedom ofmovement for assuming its proper position when inflated and at the sametime fully protecting the base of the inner air chamber unit andassisting in retaining the bases of the outer air chamber unit in properposition.

It is a further object to provide a construction which is substantiallycontinuous in outer appearance, giving the impression of a single innertube such as is on the market today; and with objectionable featurescausing the tube `failure eliminated.

It is an object to provide a construction in which the base of the innerair chamber or tube is not unduly thick, for the reason that the base isprotected by an integral flap joining the base portions of the outer airchamber unit so that a thin readily stretchab-le base of the inner airI. chamber unit is not objectionable.

It is a further object to provide a construction which may bemanufactured by either a single or double cure, as desired, which isrelatively inexpensive, and which may be made on machinery available andin use today,

'Other objects and advantages of the invention will appear as the natureof the improve-y ments is better understood, the invention consistingsubstantially in the novel construction, combination and arrangement ofparts hereinafter fully described, illustrated in the accompanyingdrawing, and finally pointed out in the appended claims.

In the drawing the figure is a fragmentary cross-sectional View of asafety tube illustrated from a perspective viewpoint, showing thefeatures of my present invention.

Referring more in detail to the gure, number I0 is an ordinary valvestem, such as is common on the market and in use today. This valve stemis inserted in and fastened to the inner air chamber unit or tube II,preferably in the same manner that valve stems are inserted in ordinaryinner tubes on the market. It is retained in place by vulcanizing orotherwise fastening the flared base portion I2, so that the inner airchamber is inflated through said valve stem.

The inner air chamber unit II`comprises a crown portion I3, side wallsI4 and I5, and a base portion I6, the parts forming an inner aircontaining chamber.

At least a part of the base portion is preferably formed of resilientmaterial such asrubber strip I'I.

As generally constructed, the side walls and crown portions of the innerair chamber unit are preferably of rubberized fabric or the like.

It is to be understood however that practically all materials used inconstruction of tubes are feasible for use in this structure, and itisnot intended to limit the scope of this application by merely describingone material for each portion of the safety tube.

Preferably joined to the outside of the inner air chamber unit I I,along the side wall portions I4 and I5, is the inner side wall I8 of theouter air chamber. This inner side wall I8 ispreferably constructed ofrubber compound such as is in use on the ordinary inner tubeconstruction today. Obviously othermaterials may be substituted, butrubber seems to be most desirable.

The inner side walls I 8, at their other edge portions, join with theouter walls I9 to form bases 20, being fastened thereto by vulcanizing,cementing or otherwise in any well-known manner. This completes theouter air chamber unit 2l which has the outer side walls 22, the crownportion 23, and completes two effective air chambers. The inner airchamber unit is sometimes called the inner tube, and has one or morepassages 24 comprising grommets or the like by which air may pass atrestricted speeds from the inner air chamber to the outer air chamber.It is thus clear that the outer air chamber unit has a portion of itsinner wall composed of crown portion I3 of the inner air chamber unit,and the remainder of its inner wall comprising the inner side walls I8.This is not absolutely necessary, but seems to be a preferred form.

The bases 2B of the outer air chamber unit 2I are joined by a flapportion 25, which preferably is acontinuation of the material formingthe outer walls I9 of the outer air chamber unit. The space 26 betweenthe flap portion and the base i6 of the inner air chamber unit IIpreferably has one or more air ports 2l, which serve to let the air owout freely from the space 26.

As shown in the gure, these air ports may comprise holes or space leftaround the valve stern I0, although there may be other ports at variouspositions if desired.

Although the material forming the flap 25 is preferably a continuationof and similar to the outer walls I9 of the outer tube, it is understoodthat the flap may be constructed of webbing of various kinds or withlarge ports 21 therein. In operation, the entire assembly is mountedwith an automobile tire, not shown, on a rim, not shown, and air isforced into the valve stern III. Rapidly filling the inner air chamberwith air causes the inner air chamber unit II to set into the well ofthe rim on which the tire and tube are mounted. For this purpose therubber strip I1 has a peculiar action in seating in the well of the rim.It is believed to stretch sideways in cross-section, and to compresscircumferentially because the inner diameter is decreased when it goesinto the well of the rim. The rapid infiation of the inner chamber isnot transmitted to the outer chamber, which fills up more slowly. As theair seeps through the passage 24, the crown portion I3 of the inner airchamber unit reaches a state of balance with respect to the air on bothsides thereof, and the base I 8 will have become firmly seated in thewell of the rim. In case of abrupt seating of the base I6, or movementwhich tends to pull the inner wall of the outer air chamber unit out ofnormal operating position, causing a fold or bend which is cornmon insome constructions of safety tubes on themarket today, the flap 25 willresist the pull of any folding movement which would tend to cause thebases 20 to move outwardly, thus keeping the inner wall of the outer airchamber unit properly aligned. 'Since the inner wall of the outer airchamber unit preferably is constructed to expand if necessary, the pullat the bases 2!! by the nap 25, in event of excessive movement outwardlyof the inner air chamber unit will hold the bases 28 in properposition.' At all times, even in failure of the outer air chamber unit2l, the base I6 of the inner air chamber unit and particularly therubber strip I'I is properly protected against rim friction andY injuryby the iiap 25.

Air chamber is generally intended herein to designate the spacecontaining air for iniiation, and air chamber unit is generally intendedto designate the structure forming the air chamber. This is true unlessthe meaning is obviously otherwise.

VThe form of the invention herein shown and described presents apreferred embodiment thereof, and delineates its adaption to practicaluse, but it is to be understood that the present disclosure is to beconsidered from the illustrative standpoint and not as imposingrestriction or limitation on the invention.

While I have herein shown and described certain features of myinvention, still I do not wish to limit myself thereto, except as I maydo so in the claims.

I claim: Y

1. An inner air chamber unit with a base, side walls, and a crownportion, and an outer air chamber unit with a plurality of bases, sidewalls and a crown portion, said outer air chamber unit surrounding thecrown portion and at least part of the side walls of the inner airchamber unit, and having its base portions fastened together by a flapacross the base of the inner air chamber unit and separate and distincttherefrom, valve means passing through the flap and attached directly tothe inner air chamber whereby the inner air chamber is iniiated withoutiniiating between the flap and the base of the inner air chamber, andmeans, in the flap, releasing at all times any entrapped air frombetween the flap and the base of the'inner air chamber, wherebysubstantial air pressure above atmospheric is eliminated from betweensaid iiap and the base of the inner air chamber.

2. An inner tube having an inner air chamber unit with base, side wallsand crown portions and an outer air chamber unit with base portions,inner walls and crown, said outer air chamber unit surrounding the crownportion and at least part of the side wall portions of the inner airchamber unit, and the base portions of said outer air chamber beingconnected by a flap across the base portion of said inner air chamber,and release means Ain the ilap, comprising air ports, wherebysubstantially all entrapped air is removed from between the flaps andthe base of the inner air chamber during normal operations when the airchambers are inflated.

3. An inner tube comprising in combination an outer air chamber unithaving cuter walls, inner walls, crown and a plurality of base portions,and an inner air chamber unit having crown, side walls and base, withthe crown and at least a portion of the side Walls comprised of andidentical with at least a portion of the inner walls of the outer airchamber unit, said inner air chamber unit base portion being separatewith respect to the base portions of the outer air chamber unit, thebase portions of the outer air chamber unit being connected by a flap,said iiap in normal operations resting against the base of the inner airchamber throughout substantially the area of the flap, but beingdistinct from said base of said inner air chamber.

4. An inner tube comprising in combination an outer air chamber unitwith inner walls and outer walls, crown and a plurality of baseportions, and an inner air chamber unit with crown, side walls and base,with the crown and at least a portion of the side walls comprised of andidentical with the inner walls of the outer air chamber unit, said innerair chamber unit base portion being separate from the base portions ofthe outer air chamber, the base portions ofthe outer air chamber beingconnected by flap means separate and distinct from the base of the innerair chamber unit, said flap having means comprising at least one port,eliminating substantially all air from between the flap and inner airchamber when the air chambers are inflated, and valve means forinilating the air chambers.

5. An inner tube comprising a plurality of air chambers formed of innerand outer air chamber units, the inner air chamber unit having a base,V

side wall and crown portions, and the outer air chamber unit having aplurality of bases, an outer wall, an inner wall, and a crown portion,the bases of the outer air chamber unit being connected by ap means,across the base of the inner air chamber unit, and means venting thespace between the flap means and the base portion of the inner airchamber unit at al1 times whereby no substantial pressure aboveatmospheric exists between the flap means and the base portion of theinner air chamber unit.

6. An inner' tube comprising a plurality of air chambers formed of innerand outer air chamber units, the inner air chamber unit having a base,side wall and crown portions, and the outer air chamber unit having aplurality of bases, an outer wall, an inner wall, and a crown portion,the bases of the outer air chamber unit being connected by ilap means ofyieldable flexible material, across the base of the inner air chamberunit, and separate therefrom, and means, in the flap, releasing air frombetween the ilap means and the inner air chamber unit wherebyatmospheric pressure is maintained at all times for any air between theflap means and the base portion of the inner air chamber unit.

7. An inner tube comprising in combination an outer air chamber unit,with inner walls and outer walls, crown and a plurality of baseportions, and an inner air chamber unit having a crown, side walls and abase, with the crown and at least a portion of the side walls of theinner air chamber unit comprised of and identical with the inner wallsof the outer air chamber unit, said inner air chamber unit having a baseportion separate with respect to the base portions of the outer airchamber unit, all of the base portions of the outer air chamber unitbeing connected by a ilap means separate and distinct from the base ofthe inner air chamber unit and across the base of the inner air chamberunit, said ilapv forming an air retaining portion of neither air chamberunit and having means comprising an outlet port, whereby substantiallyall air is prevented :from becoming entrapped between said flap and saidair chambers, and said air chambers having valve means whereby they areinilated. f

8. An inner tube of the class described having in combination an innerair chamber unit with side wall, crown and base portions, an outer airchamber unit of generally crescent shape, said outer air chamber unithaving a plurality of base portions and having an inner wall joining theouter air chamber unit to the inner air chamber unit at a position abovethe base portion of the inner air chamber unit, and a flap connectingthe base portions of the outer air chamber unit across the base of theinner air chamber unit, at least one passage for air between the innerand outer air chambers, and a valve stern from the inner air chamberthrough the ilap, by which air is conducted from a source of air such asa tire pump to the inner air chamber, and port means whereby entrappedair is removed from the space between the flap and the base of the innerair chamber, and said flap forms a protective portion over the base ofthe inner air chamber.

9. A safety tube for automobiles and the like comprising an inner airchamber unit, having side wall, base and crown portions, forming aninner air chamber, an outer air chamber unit, with base, inner walls,and crown portions forming an outer air chamber, and at least partiallysurrounding said inner air chamber, and having a portion of its innerwalls composed of the outer portion of at least a portion of the innerair chamber unit, the outer air chamber unit having strips of materialcomprising at least a portion of its inner walls joining the outer airchamber to the tube comprising the inner air chamber unit at a positionabove the base of the latter, the outer air chamber unit having its baseportions connected across the base of the inner air chamber unit bymeans of a ilap, said ilap being separated from the base of the innerair chamber unit, and having port means, eliminating substantially allair from the space between the ap and the inner air chamber duringnormal operation-especially when the air chambers are inated.

10. An inner tube comprising a plurality of air chambers formed of innerand outer air chamber units having respective base portions, the outerair chamber unit having two base portions extending below at least theupper part of the base portion of the inner air chamber unit,intercommunicating means for the passage of air between the airchambers, means comprising a flap connecting the base portions of theouter air chamber together across the base of the inner air chamber, theconnecting means being separated from the base of the inner air chamber,valve means comprising a valve stem, passing through said connectingmeans and discharging directly into one of said air chambers, saidstructure being characterized by an absence of substantial inflationbetween said connecting means and said inner air chamber.

11. An inner tube comprising an inner and an outer air chamber unit, theinner air chamber unit having a base, Side Wall and crown portion, andthe outer air chamber unit having a plurality of bases, an outer Wall,an inner Wall and a crown portion, the bases of the outer air chamberunit and the base of the inner air chamber unit being separated andspaced apart, and the bases of the outer air chamber unit beingconnected by a fiap means across the base of the inner air chamber unit,and means eliminating substantiaily al1 air pressure above atmosphericfrom the space between the outer air chamber unit base means and theflap, and the base of the inner air chamber unit, at al1 times.

FREDERICK A. KRUSEMARK.

